Lever arrangement to transmit a driving force

ABSTRACT

A lever arrangement for transmitting a driving force to a switch contact of a power switch has parallel bearing plates with limiting parts mounted on them to reduce the distance between the bearing plates locally to a distance suitable for guiding hinge-connected levers. Hinge pins of the levers are guided so they slide along the limiting parts. Threaded pins are riveted to one bearing plate at one end and are secured on the other bearing plate with a nut.

FIELD OF THE INVENTION

The present invention relates to a lever arrangement for transmitting adriving force to a switch contact of a power switch, with a springenergy store device and a plurality of levers connected by hinge pinsand arranged between the spring energy store device and the switchcontact, and with parallel bearing plates that accommodate the leverarrangement between them.

BACKGROUND OF THE INVENTION

Examples of such lever arrangements are disclosed in German patent DE-A3,542,746 and European patent EP-A 88,215. The low-voltage powerswitches described there are designed for a high switching capacity andtherefore require a very efficient switching mechanism.

OBJECTS AND SUMMARY OF THE INVENTION

One object of the invention is to design the lever arrangement so thatthe weight and cost of the power switch will be within a favorablerange.

This object is achieved according to this invention by mounting aparallel limiting part on each of the bearing plates with a spacerinserted in between, where the clearance between the limiting partscorresponds to a local width of the lever arrangement, and the bearingplates are connected by at least one retaining pin connected to each ofthe bearing plates.

These features achieve the result of a simple design of the hingesbetween the pairs of levers, in which guidance with practically no playis possible and nevertheless the bearing plates may have a spacingsuitable to also accommodate components of the lever arrangement havinga greater width. The framework consisting of the bearing plates and thelimiting parts is also characterized by a high flexural strength with arelatively low weight.

It is equally advantageous in terms of strength and ease of assembly ifthe retaining pin is riveted rigidly at one end to the respectivebearing plate and if the other end with a threaded stem passes throughan orifice in the other bearing plate and is secured with a nut.

The lever joints can be simplified by designing at least one of thehinge pins so that it corresponds to the spacing between the bearingplates, and providing the limiting parts with through-holes for hingepins.

At least one of the retaining pins can be designed as a stop to limitthe path of parts of the lever arrangement. This has the advantage thatthe force is introduced uniformly into the bearing plates.

At least one of the retaining pins can be designed to connect both thebearing plates and the limiting parts.

A suitable thrust bearing with an especially good load-bearing capacityresults from an arrangement where a stationary hinge pin of the leverarrangement rests with each end in a bearing sleeve that engages with apin in an orifice of the respective bearing plate and engages with acollar in an orifice of the respective limiting part.

The bearing plates can also be designed as an abutment for the springenergy store device and may be arranged with a distance between themthat corresponds to the diameter of the spring energy store device.

Even for the strong forces that occur in releasing the spring energystore device, the framework can be set up by arranging two pairs of endfaces opposite a pressure plate of the spring energy store device as theend stop, where one pair is formed by the limiting parts and the secondpair is formed by two guide partitions attached to the bearing plate.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention described above and additional featuresare described in greater detail below with respect to the embodimentillustrated in the drawings, of which:

FIG. 1 is a schematic diagram of a lever arrangement for a low-voltagepower switch.

FIG. 2A is a front view of an arrangement of bearing plates and limitingparts to accommodate the lever arrangement.

FIG. 2B is a magnification of a portion of the view shown in FIG. 2A.

FIG. 3 is a front view of an arrangement corresponding to that in FIG.2A, with bearing plates and limiting parts shown together with a leverarrangement.

FIG. 4 is a side view of a single bearing plate with a limiting partriveted to it and with a guide partition.

DETAILED DESCRIPTION

The lever arrangement shown schematically in FIG. 1 serves to operate aswitch contact arrangement having a movable contact lever 1 and astationary counter-contact 2. Movable contact lever 1 is hinge-connectedto a lever support 3 that is mounted so it can pivot and is providedwith a contact force spring 4. Two toggle levers 5 and 6 provide a hingeconnection for the lever support 3 to an operating shaft 7 that isprovided jointly for a plurality of poles of a power switch. Accordingto the "off" position of lever support 3 illustrated here, the togglelevers 5 and 6 are shown in a bent position where toggle lever 6 isresting against stop 10.

A hinged joint 11 between toggle levers 5 and 6 is acted on by otherlevers that are common to all the poles of a power switch and have thefunction of providing the total operating energy required. For thispurpose, a spring energy store device 12 designed as a helicalcompression spring is provided and abuts against surface 12A. Springenergy store device 12 is loaded by means of a cam plate 13 incombination with toggle levers 14 and 15 whose connecting joint 16 isacted on by cam plate 13 by means of a roller 17 (shown with dottedlines). In the position according to FIG. 1, toggle levers 14 and 15 arealmost in their fully extended position, so spring energy store device12 is loaded and ready for use. A supporting lever 20 that acts onhinged joint 16 is supported by means of a two-step contact latch, whichincludes a contact half-shaft 21, a pivotable main contact latch 22, aroller lever 23 connected to main contact latch 22 and an auxiliarylatch 24 connected to supporting lever 20.

Another lever system positioned approximately parallel to theabove-mentioned parts connects spring energy store device 12 to hingedjoint 11 between toggle levers 5 and 6. This lever system also includesa driving lever 25 connected to spring energy store device 12 and havinga driver 26 and a free-wheeling link 27 which, like driving lever 25,can be pivoted about a stationary bearing pin 30. Free-wheeling link 27supports a stop part 31 that works together with a stationary stop 32.Free-wheeling link 27 is connected to hinged joint 11 by way of twoother hinged joints 33 and 34, with joint 35 between toggle levers 33and 34 being supported on an auxiliary tripping latch 37 via supportinglever 36. In the position of the lever system shown here, the auxiliarytripping latch is in contact with a roller lever 40 of a main trippinglatch 41 that is held by a tripping half-shaft 42.

FIG. 2A illustrates an example of a framework that can accommodate thelever arrangement illustrated in FIG. 1. The framework has two parallelbearing plates 43 and 44 at right angles to operating shaft 7 (FIGS. 1and 3). The distance between bearing plates 43 and 44 is such thatspring energy store device 12 can be accommodated between them. Bearingplates 43 and 44 can be designed to serve as abutments for the springenergy store device 12, and bearing plates 43 and 44 may be arrangedwith a distance between them that corresponds to the diameter of thespring energy storage device 12. At several locations on bearing plates43 and 44 there are mounting elements (also referred to as retainingpins) 46, each of which consists of a spacer pin riveted to bearingplate 43 and having a threaded stem 47 at the end. This arrangement incombination with a nut 50 on each element yields a bending-resistant,i.e., rigid, connection of bearing plates 43 and 44.

Limiting parts 51 and 52 are attached by means of a plurality of spacers53 to bearing plates 43 and 44 above spring energy store device 12. Thiscreates a lateral guidance with little play for the entire leverarrangement. At the same time, this guidance is especially stable withrespect to lateral forces because limiting parts 51 and 52 that are eachriveted to one of the bearing plates provide a considerablereinforcement of the framework. At least one of the mounting elements 46can be designed to connect both the bearing plates 43 and 44 and thelimiting parts 51 and 52.

Hinge pins 54 (FIG. 3) which form the hinges between toggle lever 33 andfree-wheeling link 27, for example, and between supporting lever 36 andauxiliary tripping latch 37 (FIG. 1) pass through orifices 55 (FIG. 4)in limiting parts 51 and 52 and are designed so that they are guided onbearing plates 43 and 44. As FIG. 4 shows, a section of limiting part 52extends beyond the contour of bearing plate 44. In this area, limitingpart 52 and the other limiting part 51 that is not visible in FIG. 4 areprovided with an debossed section 56 that serves as a guide face for ashorter hinge pin. An appropriate projecting length of the hinge pinover the lever that is guided in this area is made possible by debossedsection 56. Such a shorter hinge pin can be provided for hinged joint11, for example (FIG. 1).

The magnified view presented in FIG. 2B shows how a stationary hinge pinof the lever arrangement, which may be bearing pin 30 in FIG. 1, issupported in the framework. This is accomplished by means of two bearingsleeves 60 (also referred to as bushings) having a blind hole 61 for abearing pin. Bushings 60 are riveted to bearing plates 43 and 44 as wellas limiting parts 51 and 52. For this purpose, each bearing sleeve 60has a pin 62 and a collar 63. Each bearing sleeve 60 thus engages withits corresponding pin 62 in an orifice of a corresponding one of thebearing plates 43 and 44. Further, each bearing sleeve 60 engages withits corresponding collar 63 in an orifice of a corresponding one of thelimiting parts 51 and 52.

As mentioned previously, spring energy store device 12 is accommodatedbetween bearing plates 43 and 44 in the lower area of the framework. Aspecial design assures that the considerable forces occurring in thisarea upon the release of spring energy store device 12 can be absorbedwithout damage to the framework. For this purpose, limiting parts 51 and52 according to FIG. 4 are each provided with a stop face 64 whileanother stop face 65 is designed on each guide partition 66 and 67mounted so that they are approximately aligned with limiting parts 51and 52 by means of additional spacers 53 (FIG. 3). Guide partitions 66and 67 accommodate toggle levers 14 and 15 between them (FIG. 1) andform a stop for hinge 16 of roller 17. A pressure plate 70 that restsagainst all four stop faces mentioned above is indicated schematicallyin FIG. 1.

Another measure in the area of spring energy store device 12 which isalso illustrated in FIG. 1 reduces the stress on stop faces 64 and 65.This is accomplished by uncoupling the entire lever arrangement fromspring energy store device 12 to a certain extent and thus preventingthe entire moving mass of the lever arrangement from acting on the stopfaces. Therefore, a push-rod 72 that extends into the inside of springenergy store device 12 where it supports end piece 73 is connected to ahinge 71 that is mounted on pressure plate 70 and acted upon togglelever 15 and driving lever 25. End piece 73 is opposite a pot-shapedstop 74 that is connected to pressure plate 70 and thus ensures thetransmission of forces between these levers and spring energy storedevice 12. At the opposite end, however, end piece 73 is supported onthe inside of pressure plate 70 by way of spring elements 75. Thesespring elements are designed as pairs of disc springs.

As this shows, the arrangement of spring elements 75 makes it possiblefor joint 71 to continue moving to a certain extent under the influenceof the kinetic energy of the levers connected to hinge 71 when pressureplate 70 is already in contact with stop faces 64 and 65. This reducesthe stress on the stop faces and the entire framework as well as all thehinge pins and bearing pins.

We claim:
 1. A lever arrangement for transmitting a driving force to a contact lever of a power switch, comprising:a spring energy storage device; a plurality of levers connected by hinge pins and arranged between the spring energy storage device and the contact lever; parallel bearing plates accommodating the levers between said plates; a parallel limiting part mounted on each of the bearing plates with a spacer between each limiting part and the bearing plate on which it is mounted, wherein the limiting parts define a clearance therebetween corresponding to a local width of the lever arrangement, and the bearing plates are connected to each other by at least one retaining pin rigidly connected to each of the bearing plates.
 2. The lever arrangement of claim 1, wherein one end of the retaining pin is rigidly riveted to one of the bearing plates, and an opposite end of the retaining pin includes a threaded stem passing through an orifice in the other bearing plate and secured by a nut.
 3. The lever arrangement of claim 1, wherein at least one of the hinge pins is configured to correspond to the distance between the bearing plates, and the limiting parts are provided with through-holes for receiving said hinge pin.
 4. The lever arrangement of claim 1, wherein the at least one retaining pin is so dimensioned that the retaining pin limits the path of parts of the lever arrangement.
 5. The lever arrangement of claim 4, wherein the at least one retaining pin connects the bearing plates to each other and the limiting parts to each other.
 6. The lever arrangement of claim 1, further comprising a stationary hinge pin having ends positioned in bearing sleeves, said bearing sleeves each having a pin engaging an orifice in one of the bearing plates and having a collar engaging an orifice in one of the limiting parts.
 7. The lever arrangement of claim 1, wherein the bearing plates comprise abutments for the spring energy storage device, said bearing plates being arranged with a distance therebetween corresponding to the diameter of the spring energy storage device.
 8. The lever arrangement of claim 7, further comprising two pairs of stop faces arranged opposite the spring energy storage device as a final stop, with one pair formed by the limiting parts and the other pair formed by two guide partitions mounted on the bearing plate.
 9. The lever arrangement of claim 1, further comprising a pressure plate and a hinge on a movable end of the spring energy storage device for connecting the spring energy storage device to a toggle lever that supplies stored energy to a driving lever that transmits the stored energy in the direction of the contact lever, said lever arrangement further comprising a push-rod extending inside the spring energy storage device and connected to the hinge, said push-rod including an end piece opposite a stop rigidly connected to the pressure plate and also opposite the pressure plate, wherein a spring element is positioned between the stop and the pressure plate, the spring element having a high spring constant relative to the spring energy storage device.
 10. The lever arrangement of claim 9, wherein the spring element comprises pairs of disc springs, and wherein the stop is pot shaped and is rigidly connected to the pressure plate at an edge thereof. 